Persons may forget a birthday.Logical formLearned from21 sentences. Yesterday can be (birthday ..).Logical formLearned from21 sentences. (Birthday gifts) can be belated.Logical formLearned from21 sentences. A (birthday dinner) can be for a female.Logical formLearned from21 sentences. Some months can be until a birthday.Logical formLearned from21 sentences. Birthdays can be missed.Logical formLearned from21 sentences. Persons can be at a (birthday party).Logical formLearned from21 sentences. Birthdays can be good for a person.Logical formLearned from21 sentences. A person may pass a birthday.Logical formLearned from21 sentences. A mom may celebrate a birthday.Logical formLearned from21 sentences. A person may remember a (birthday party).Logical formLearned from21 sentences. A birthday can be at a home.Logical formLearned from21 sentences. A daughter may have a birthday.Logical formLearned from21 sentences. (Birthday cakes) may pertain-to persons.Logical formLearned from21 sentences. A person may sing birthday to a female.Logical formLearned from21 sentences.